Question

What makes enforcing safety standards a challenge for the food and drug administration?

Answer 1

Enforcing safety standards is a challenge for the food and drug administration because many foods are imported from other countries, and the FDA must ensure those foods meet the same standards as US goods.

Answer 2

What makes enforcing safety standards a challenge for the food and drug administration is that many foods are imported from other countries, and the FDA must ensure those foods meet the same standards as US goods.
All of these foods must be checked so as to avoid any troubles with the consumers who will buy and eat the food.